US2490108A - Apparatus for continuously separating solids of explosive from liquid - Google Patents

Description

L. E. WALKUP 2,490,108 APPARATUS FOR CONTINUOUSLY SEPARATING SOLIDS 0F EXPLOSIVE-FROM LIQUID Filed March 24, 1942 INVENTQR Lewis E.Wa.Ikup

ATTORNEY Patented Dec. 6, 1949 -'APBARATUS FQR'CGNTINUQUSLY SEPARAT- IN-G; SOLIDS 'OFEXPLOSIVEFROM LIQUID Wood R e .11.- es i nori to Q 3 ndu tri s. n a, cqrporatie o D l Application March .24, 1942, sefia1 No; 435,003 scam hm-Tee This invention .relatesqto the manufacture of explosives and in partic llflrto ,the separation of explosive particles ,from a slurry.

, In the manufacture of explosives, in accordance with, some processes,. :smallparticles of the solid explosive are in contacts with or suspended in lar to1u s, .,l.-id a mu t b se te therefrom before they can be further treated or .used.

=,Simple,decantation methods, are operative for th purpo o ywithiex lqs reslhavi g a t n .ency to completely settle out, of their liquid slurri and they. er in-additie -th d sa nt g of requiring appreciableperiodsof time for such settling out and-ofier difiiculty in; obtaining a complete separatio oi. h w iq id ro t e plosive.

Continuous vacuum type ,filters such ;as the rotary filter, and batch typeseparators;,such as the intermittently .operated,eentrifugabseparators, have been employed kfoiysuch, purpeses,-. but methods employing such filters areattended with serious disadvantages in the: manufacture, of; expl s ve eh ftame e whic ma cab me t o e high cost of operation, low production capacity, and in the casepf the continuous vacuum type filter, difficulty incontroldue to the critical proportions oi slurry-necessary for satisfactory fumetioning.

It is an object ofgthis invention to provide a p c for ea ytsecurine. efieeti e. s paration of particlesof -.e ;xp1osiye from a liquid.

Another obj ect ot, the invention ;.is :to -;provide es and unee pl eeted e rif e ap a a u for continuously separating the components-pf a slurry composed ,of. -particles of, =explosive ;;in a liquid.

Still another object. of this;inventionis -;to -provide an economical --method ;and;-means fpn =the continuous separation of- :particles of explosive from an associated liquidyvhile; ailjording-opportunity for fu rthertreatrnent with a treating liquid during the separationprocess.

A still further object of the inventioniis taprovide an economical method for-continuously treating particles of.explosivewith-a-liquid for a very short period of-time, andthereafter separating the particles of explosive from the. liquid.

Other objects. will \be apparent from ;=.the acoompanying description and drawings, of which Fig. 1 is a verticalsection of a centrifugallseparator embodying thisinvention, and

Fig. 2 is a vertical sectionoi therotarylcontamer illustratin t ecformiakemby,thee sive, and

,F fig 3 1s, a ,vertical sectionof a modified centrifugal separator embodying the invention.

In accordance with the present inventionthe above stated objects are, accomplished by con- ,tinuously feeding; a slurry of the explosive particles into a rapidly rotating-container having substantially cylindrical perforated side walls, providing/means for continuously collecting and dischargingtheliquid passingthrough the perfo ratior s, ar1d providing means for continuously ,cpllecting and discharging the substantially liquid-free explosive propelled from the mouth of the container. When an intermediate treatment with a liquid is desired, means are provided for spraying wash waterorother liquid toward .the inner surface ofthe-side walls of the container during the process.

, It hasnow been found thatifa-slurry of explosive particles is fed continuously into arapidly rotating container having substantially eylindrical rperforated sidewalls, ,the explosive, as it loses its slurry Jiquid through the perforations, first forms a; lining having, aconoidal surface in the container and then subsequently f ed, particles :e r h. a o e th ssurfa e an .are pr e e ward-1y from the- -mou thof the pontainerover t fed e 0 t e 1 1 e- ,1, e ini :a i-e ple esbe n oun o s v es-e :ide efil be .f t s u et ini xp s ve; rti isme zit en th rfora n in thepontainer walls and preventing larger parti s em elesshe.;.th ;her e eh 9 Fu the it. heslee n un h lt exp o iv may be washed or otherwise treated-with aliquid byish e i t we i-We s r o h r li ehlt linin ex siv articular y,ent eu per. p r tie the eo durin the s pa atin o rati Thhe-a eer ihe o; t s-i eh e th sl of explosive can be continuously fedinto the -rotati e ehtei-herge.. 'qu e nteh th he v e ih t oug ;v the-p orat o s .be ver e t .the se er. e e ewh e sw e ir rhi th na iel sef subst n i l qu e .e e eer n nu us y pr el fro em e hlofi th eehte n ehd l n be. e e e and eeht znheus conveyed away for furthertreatment-or use.

,;-.A1;n0 vel, centrifuge developed-for carrying out th pr e p t s invent o ,i 11 sh'e 1. i Eigures 1 2 and 3, in which apontainer 13 havthe ti n r re bette 1-. a e ih rie perforate side walls 3 is mounted for rotation about-thelongitudinal axis on a rotary shaft l. A housing dismounted about, the periorate por tion ,3 of the container [3 and is adapted tQ-collect the liquid passing through the perforations and to discharge same through the outlet 6. The annular receptacle 4 with walls I and discharge outlets 9 is mounted about the mouth of the container I3 and-is adapted to collect and discharge particles of explosive propelled from the mouth of the container l3. A feed pipe 8 is provided to inject the slurry of explosive into and near the bottom 2 of the container l3. Liquid inlet pipe I4 is provided to spray wash water or other liquid toward the side walls 3 of the container l3.

In Fig. 2, the line IE] illustrates the conoidal surface of the lining of the explosive in the container l3, and application of a treating liquid to the explosive is shown at H.

In Fig. 3, a variation in the container I3 is illustrated in which a series of large perforations l2 are located at the mouth of the container 13 and above the perforate side walls 3. The perforations i2 are designed to permit passage of the substantially liquid-free explosive into the annular receptacle 4.

The housing 5 may be subdivided into one or more receptacles l5, I6, I? and 18 with discharge outlets 6, I9, 20 and 2!, for the purpose of separating the slurry liquid from the wash water, or other treating liquids, expelled from the side walls 3 of the container.

By way of illustration, following is a description of the use of the process and apparatus of this invention on substantially spherical particles of smokeless powder prepared for instance according to the process described in U. S. Letters Patent 2,027,114, wherein a powder base is suspended in water in the presence of a solvent for the powder base and after agitation and heating to remove the solvent, small spherical gelatinized grains of smokeless powder suspended in water result.

In separating such powder from its slurry liquid, a rotary container l3 about seven inches in diameter and six inches high was employed. The side walls 3 of the container were perforated with one quarter inch holes, all but the top annular row of holes l2 near the mouth of the container being covered with fine mesh Dutch-weave screen. A slurry containing about 50% by weight of powder was fed into the container near the bottom and a lining of powder having a conoidal surface was immediately built up in the container, the surface of the lining having an angle of about 25 to the sidewalls. Immediately after formation of the lining, substantially liquid-free powder was propelled from the container through the annular row of perforations l2 about the mouth of the container. At the same time the powder slurry was being fed into the container, wash water was sprayed from inlet I 4 onto about the upper half of the powder lining. In this way the powder, which lost its slurry liquid relatively near the bottom 2 of the container, was washed substantially free of any residual slurry liquid constituents while traveling up the surface of the lining through the spray of wash water to the perforations l2. Washing in this manner was found to be very efiicient requiring only a small portion of water per unit weight of powder.

The liquid passing through the perforations, which included both the slurry liquid and the wash water, was diverted to a storage vessel for recovery of the treating reagents contained therein.

The powder propelled through the annular row of perforations l2 at the mouth of the container was substantially free of all but the occluded '4 liquid and had an average moisture content of only about 9.5%. The container was rotated at the relatively low speed of about 800-900 revolutions per minute and even at this low speed the capacity was found to be about 35,000 pounds of liquid-free powder per 24 hours. The production capacity could be considerably increased by raising the speed of rotation. The continuous centrifugal separator required a much smaller space and only a fraction of a horsepower for operation whereas a vacuum type rotary filter having much lower production capacity was found to require about 22 horsepower. The effectiveness of this process is demonstrated by the fact that the 9.5% residual moisture content is the same as that obtained by centrifuging a lot of the same powder in a batch centrifuge for 4% minutes at 1900 R. P. M.

Although in the above specific example, the process and apparatus of this invention are described for use on spherical gelatinized grains of smokeless powder it should be understood that the invention may also be employed with other explosive materials such as bulk smokeless powders, for instance made according to the process described in U. S. Letters Patent 2,235,298, tetryl and other explosive particles, particularly of substantially spherical or oval shape or agglomerates of roughly spherical configuration.

The process and apparatus of this invention may likewise be employed to continuously treat even substantially dry particles of explosive with one or more liquids for relatively short periods of time, in which case the particles of explosive may be fed, for instance through feed pipe 8, into the container simultaneously with the treating liquid, which may be fed through one or more inlets [4, while the treated and substantially liquid-free explosive is continuously propelled from the mouth of the container.

As shown in Figure 3, the process and apparatus may be readily adapted for maintaining a separation of the slurry liquid from the wash water or other treating liquid, which is of decided advantage in some instances for recovery or other purposes.

A distinct advantage in having the explosive material form the lining in the rotary container is that depending on its angle of repose each explosive forms its own slope at just the angle necessary to permit the particles to climb to the mouth of the container and an ideal filter bed for separating the explosive slurry is thereby provided. Further advantages as described above are increased economy of operation and increased production capacity.

Since many variations may be made in the specific embodiments described therein without departing from the spirit and scope of the invention, it should be understood that the invention is not limited to the details thereof except as set forth in the appended claims.

Having now described the invention, what is claimed as new and is desired to be covered by Letters Patent is:

1. Apparatus for continuously separating grains of explosive from an associated liquid, comprising the combination of a container having an imperforate bottom and substantially cylindrical perforate side walls with a conoidal-surfaced lining of said grains and mounted for rotation about its longitudinal axis, a housing mounted about said container and adapted to continuously collect and discharge liquid passing through the lining and perforate side walls of said container, an

annular receptacle mounted about the mouth of said container andadapted to continuously collect and discharge the substantially liquid-free grains of explosive propelled from the mouth of said container, and means for rotating said container.

2. Apparatus for continuously separating smokeless powder grains from a slurry thereof, comprising the combination of a container having substantially cylindrical perforated side walls with a conoidal-surfaced lining of said grains and mounted for rotation about its longitudinal axis, a housing mounted about said container adapted to continuously collect and discharge liquid expelled through the lining and perforations in said container, an annular receptacle mounted about the mouth of said container and adapted to collect and discharge the grains of explosive propelled from the mouth of said container, means for forcing a liquid toward the inner perforate surface of said container and means for rotating said container.

3. Apparatus for continuously separating grains of explosive from a slurry thereof, comprising the combination of a container having substantially cylindrical perforated side walls with a conoidal-surfaced lining of said grains and mounted for rotation about its longitudinal axis, a housing mounted about said container and provided with a plurality of compartments adapted to collect and separately discharge liquids expelled through the lining and perforated side walls of said container at different elevations, an annular receptacle mounted about the mouth of said container and adapted to collect and discharge the grains of explosive propelled from the mouth of said container, means for forcing liquid toward the inner perforate surface of said container, and means for rotating said container.

4. Apparatus for continuously separating grains of explosive from an associated liquid, comprising the combination of a container having an imperforate bottom and substantially cylindrical perforate side walls with a conoidal-surfaced lining of said grains and mounted for rotation about its longitudinal axis, a housing mounted about said container and adapted to continuously collect and discharge liquid ejected through the lining and perforations in said container, an annular receptacle having an outlet in its bottom mounted about the mouth of said container for continuously collecting and. discharging the grains of explosive propelled from the mouth of said container, and means for rotating said container.

5. Apparatus for continuously separating grains of explosive from an associated liquid, comprising the combination of a container having an imperi'orate bottom and substantially cylindrical perforate side walls and mounted for rotation about its longitudinal axis, a porous lining of granular material in said container presenting a conoidal surface having a slope substantially equal to the angle of repose of the said grains of explosive, a housing mounted about said container and'adapted to continuously collect and discharge liquid ejected through the lining and perforations iii-said container, a receptacle having an outlet in its bottom mounted about the mouth of said container for continuously collecting and discharging the grains of explosive propelled from the mouth of said container, and means for rotating said container.

LEWIS E. WALKUP.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 328,190 Cloudman Oct. 13, 1885 541,573 Selwig June 25, 1895 710,607 Peterson Oct. 7, 1902 781,926 Wiley Feb. 7, 1905 931,749 Gentieu Aug. 24, 1909 1,545,832 Hofibauer July 14, 1925 1,963,712 Moore June 19, 1934 2,119,644 Miller June 7, 1938 2,292,469 Olsen Aug. 11, 1942 v FOREIGN PATENTS Number Country Date 1,812 Great Britain A. D. 1877 1,007,787 Germany Jan. 4, 1899 OTHER REFERENCES Weaver, "Military Explosives" (N. Y., 1917), an ed.', p. 125.

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